A 100 mL solution was made by adding 1.43 g
of Na2CO3.xH2O. The normality of the solution
is 0.1 N. The value of x is _____.
(The atomic mass of Na is 23 g/mol)
Answer (integer)
10
Solution
Molar mass of Na<sub>2</sub>CO<sub>3</sub>.xH<sub>2</sub>O
<br><br>= 23 × 2 + 12 + 48 + 18x
<br><br>= 46 + 12 + 48 + 18x
<br><br>= (106 + 18x)
<br><br>As n<sub>factor</sub> in dissolution will be determined from net cationic or anionic charge; which is 2
<br><br>Eq wt = ${M \over 2}$ = (53 + 9x)
<br><br>volume = 100 ml
= 0.1 Litre
<br><br>Normality = <span style="display: inline-block;vertical-align: middle;">
<div style="text-align: center;border-bottom: 1px solid black;">No. of equivalents of solute</div>
<div style="text-align: center;">Volume of solution (in L)</div>
</span>
<br><br>$\Rightarrow$ 0.1= ${{{{1.43} \over {53 + 9x}}} \over {0.1}}$
<br><br>$\Rightarrow$ 53 + 9x = 143
<br><br>$\Rightarrow$ 9x = 90
<br><br>$\Rightarrow$ x = 10
About this question
Subject: Chemistry · Chapter: Redox Reactions · Topic: Oxidation States
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